1. Technical Field
The disclosure relates to light emitting devices and, more particularly, to a light emitting diode (LED) unit.
2. Description of Related Art
LEDs (light emitting diodes), available since the early 1960's, have been increasingly used in a variety of application fields and are intended to be a high quality replacement for conventional light sources due to high light-emitting efficiency, environmental friendliness, and low power consumption.
A typical LED includes a light emitting chip and a lens covering directly the light emitting chip. Light emitted from the light emitting chip is adjusted by the lens within a large region. However, the light within the large region cannot satisfy a converged illumination demand. An additional lens is provided to cover the lens and the light emitting chip. The addition lens converges the light output from the lens within a small region to obtain a desired illumination effect.
However, two lenses are needed to adjust the light emitted from the light emitting chip, thus increasing the cost of the LED. In addition, the light emitted from the light emitting chip travels through such two lenses, thus inevitably resulting in a loss of light intensity.
What is needed, therefore, is an LED which can overcome the limitations described above.